Enamel and process of making the same.



UNITED STATES-PATENT OFFICE.

Max MAYER, on BEnLm-TEmELHoF, am)

GERMANY, ASSIGNDBS T CHEMISCH-METALLURGISCHE INDUSTRIE GESELLSCHAFT m nnscHnmx um. i

No Drawing.

To all whom it may concern causethe enamel to become pire and a subject of the King of Hungary,

respectively, and residents, respectively, of,

Berlin-Tempelhof, German and Berlin- Schiineberg, Germany, have invented certain new and useful I and Processes of Making the Same, of which the following'is a specification.

It has heretofore been proposedfthat titanic acid might be used as an 'opaquing medium for white colored suggestion was made 'to use pure calcined titanic acid alone for the ostensible purpose of producing a completely covering white enamel. The idea that titanic acid would not only opaque but also white in color was, however, found to be erroneous'because instead of impartmg a .white color it made the enamel more or less yellow in appearance.- It was then proposed that cobalt titanic acid to produce'a white color, accordl0 'tive adjustment required with respect to the to the amount of 7 of accident that colors was had.

mg to the theory that the blue color of the cobalt would compensate the yellow color of the titanic acid and the resultant color This process (see German amount of cobalt oxid to be used relatively titanic acid. It was only 1n the rarest cases and largely as the result a proper compensation of Practically, therefore, the use of titanic acid in the sense of a substi-' tute for tin oxidin the production of an opaque white enamel was found to be impossible. It was further suggested that the titanic acid salts of calcium and barium be employed but it was found that while cal cium titanate. produces a beautiful creamcolored enamel and barium titanate a yellow-white color neither resulted in the clear white so much desired. Furthermore barium- "titanate is commercially valueless for the purpose, because 1t cannot be used for the production of hyg1enic enamels, that is, such for example, as 'aresafe for lining utensils used as containers for food.

From this resume of the prior state of the art it will be seen tha expected of titanic bringing about an opaque white-color in the Specification of Letters lPatent.

the German Em that titanic acid could Improvements in Enamels enamels and the dxid be added to the burn ng in of the although much was acid as a means for effects but with HAr'rUNG, or BERLIN, GERMANY, A conronarron or GER- ENAMEL AND rnocnss or AKING 7min SAME.

Patented Mar.

Application filed May 29, 1913. Serial No. 770,593.

enamel, no results of this kind were actually accomplished. The hope and expectation be used for this purpose was frequently method of getting the result has ever been described so far as we know.

We have now discovered that in spite of I titanic acid as described, this acid will nevertheless produce the desired effect if it BELA Haves, or snnLm-scnonnnnno,

expressed but no be suitably mixed with zirconium .oxid.

When accompanied by this .oxid the titanic oxid will produce a beautiful enamel opaque and absolutely white in color throughout.

hese ingredients or media for producing a white, opaque appearance are ground up in the usual manner with the coating enamel in the mill. Chemically they react only to a slight degreenot so as to injuriously affeet any of the components of the enamelso that in this respect the mixture of titanic acid: (or oxid) and zirconium oxid may be called neutral. The manner in which these substances produce the cloudy effect seems to be very largely mechanical 'ina uch as they are uniformly distributed in a. state of very fine subdivision in the melt during the enamel coating. It 1s obvious that the substances to be used (titanic acid mixed with zirconium oxid) mustbe m suchphysical condition as will make them suitable for the purpose desired. The titanic acid, or titanium 'dioxid (TiO provided it is practically free from iron, may contain silicic acid and also alkalis.

he composition substances may vary to some extent in accordance with the constitution of the covering enamel which is employed. If desired, moreover, the above mentioned mixture may be glowed or calcined-beforeuse. In place of zirconium oxid equivalent metallic compounds of the samecharactermay be employed. --For instance, a substance containing zirconium oxid may used, containing for example of zirconium oxid,

some alkali, silicic acid and water of hydration. In some casestin oxid, a member of the titanium group may be used as a sub% stitute or equivalent of'zirconium oxid.

The; use. of a' mixture of titanic acid and zirconium' oxid, as described, is commercially valuable as producing not only superior substances which are materially cheaper to of the mixture of the two produce than those hereto fore used in connection with such white enamels as this applicationcontemplates.

The following example is given to show specifically the composition of an enamel suitable for producing the white, opaque effeet in accordance with our invention, it being understood, of course, that these examples are 'merely illustrative and are not to be regarded as limiting our invention.

Ewample.

The body of the enamel is prepared according to the usual practice and under well understood conditions by melting together To this melted enamel during grinding in the mill, and for each 100 kg. of the same, are added 7 kg. of enamel clay and 6 kg. of the opacity medium, the latter consisting of a mixture of 1%,; kg. of titanic acid and 4%; kg. of zirconium oxid. As described, the opacity medium may be previously heated and the zirconium constituent replaced in about the same quantities ample by an oxid of the titanium group,

given 1n the exsuch as tin about 85% being free from iron.

In the claims the expression a titanic oxid is intended to include the hydrated aswell as the anhydrous oxid and the expression embraces the zirconium; oxid variants or equivalents of the same.

We claim:

1. That improvement in the art of producing an opaque white enamel, which consists in adding to the ena-meling material a mixture of a titanic oxid with zirconium oxid.

2. That improvement in the art of producing an opaque white enamel, which con sists in adding to the enameling material a mixture of a titanic oxid with a suitable substance containing zirconium oxid.

3. An opaque white enamel comprising, as the medium for producing white opacity, a mixture of a titanic oxid with zirconium oxid.

In testimony whereof, we have hereunto set our hands in scribing witnesses.

MAX MAYER. BELA HAVAS.

Witnesses:

HENRY HASPER, WQLDEMAR HAUPT.

of zirconiumoxid, the compound the presence of two suboxid or a composition containing 

